Sedimentation apparatus

ABSTRACT

An improved sedimentation apparatus is disclosed. The sedimentation apparatus comprises a container with a lower outlet for discharging sediment and a rotating scraper for moving the sediment towards the outlet. The scraper is connected by a shaft to a drive motor resiliently mounted on the container. The drive motor is pivotally mounted relative to the shaft. When resistance to scraper movement increases because of an accumulation of a certain quantity of sediment, the motor swings in relation to the shaft and actuates means to open the outlet. When a certain quantity of the sediment is removed, the motor returns to its normal position and the outlet closes.

Gustavsson et al.

SEDIMENTATION APPARATUS lnventors: Karl Axel Goran Gustavsson; KnutMelker Evald Tornqvist, both of Enkoping, Sweden Assignee: AktiebolgatBahco Ventilation, Enkoping,

Sweden Filed: May 13, 1970 Appl. No.: 36,787

Foreign Application Priority Data Field ofSearch ..210/ll2, 113,528

[451 Apr. 4, 1972 {56] References Cited UNITED STATES PATENTS 1,665,0814/1928 Andrews ..210/ll2 Primary Examiner.lim L. DeCesare AttorneyBirch,Swindler, McKie & Beckett [S 7] ABSTRACT An improved sedimentationapparatus is disclosed. The sedimentation apparatus comprises acontainer with a lower outlet for discharging sediment and a rotatingscraper for moving the sediment towards the outlet. The scraper isconnected by a shaft to a drive motor resiliently mounted on thecontainer. The drive motor is pivotally mounted relative to the shaft.When resistance to scraper movement increases because of an accumulationof a certain quantity of sediment, the motor swings in relation to theshaft and actuates means to open the outlet. When a certain quantity ofthe sediment is removed, the motor returns to its normal position andthe outlet closes.

4 Claims, 2 Drawing Figures PATENTEDAPR 4 I972 SHEET 1 []F 2SEDIMENTATION APPARATUS The present invention relates to a sedimentationapparatus in the form of a container having a central lower outlet forremoving sediment (sludge) from the container and a rotating scraperwhich serves to move the sediment towards the outlet.

An object of the invention is to provide an apparatus for automaticallyopening the bottom outlet of the container when a certain quantity ofthe sludge has settled therein, so that the sludge can be removedthereby. This is achieved by means of the present invention, which ismainly characterized in that the motor which drives the scraper ispivotally mounted in relation to the shaft of the scraper and isconnected with the container solely by means of a resilient memberwhich, upon increased resistance against movement of the scraper,permits the motor to swing in relation to the shaft, and in that themotor is connected with means which cause a valve mounted in the ,outletto open when the motor is deflected to a predetermined extent.

When a certain quantity of sludge has settled in the container and, as aresultthereof, theresistance to scraper movement has reached adetermined value, the motor as it swings will thus initiate the removalof a determined quantity of the sludge from the container. As soon asthe motor swings back, discharging of the sludge ceases.

If the container is filled with a liquid which contains solid materialand the scraper is kept inactive for a certain period of time, thefirmer material normally settles to the bottom of the container in theform of a relatively solid mass, which when the motor is started isliable to present an unnormally high resistance to scraper movement,even though the quantity of sludge present is less than that which isnormally discharged. To prevent in this case a large quantity of liquidfrom being removed as a result of the outlet being opened immediatelythe scraper is set into operation, the motor can be connected to afurther actuating means which closes the outlet in the event of themotor making a heavy swing. This arrangement is also of value should thescraper meet some other form of obstacle, in spite ofa low sedimentlevel.

The invention will now be described in more detail with reference to theaccompanying drawing, in which:

FIG. 1 shows a sedimentation apparatus seen in vertical cross section;and

FIG. 2 is a perspective view, in larger scale, of certain portions ofthe apparatus.

The sedimentation apparatus includes a container having a cylindricalmain portion 1 and a conical bottom portion 2, at the centre of which isarranged an outlet 3. Liquid containing solid material to be separatedtherefrom is passed to the container by appropriate means (not shown)while liquid freed from solid material is passed from the container byan outlet (not shown), for instance in the form of a spillway.

Mounted in the sludge outlet 3 is a rotatable throttle means 5, which isoperated by means of a cylinder 6, the piston rod 7 of which isconnected via an arm 8 to the throttle 5. The medium operating thecylinder is passed to and from the cylinder by lines 9, 10, via aconventional type of reversing valve indicated at 11.

Mounted in the upper portion of the container 1 is a frame structure 12,which supports at the centre thereof a vertical tube 13, through which ashaft 14 extends. The shaft 14 supports a scraper 15, which as the shaftrotates passes over the conical bottom 2 of the container and movessettled solid material towards the centre thereof, at which the outlet 3is located.

The shaft 14 is journalled in the inner portion of the tube 13 by meansof a ball bearing 16 (FIG. 2) and is connected to the output shaft of anelectric motor 17. The motor 17 rests on a coil spring 18, which ismounted about the upper portion of the shaft 14. The lower end 19 of thespring is securely connected with the frame 12 while the upper end 20 ofsaid spring is securely connected to the motor by bending the ends ofthe spring axially and passing said ends into holes in a plate 21cooperating with the frame 12 and in a plate 22 connected securely tothe motor. The motor has no other connection with the container] or theframe 12. Thus, the motor can swing about the centre line of the shaft14, although the spring 18 endeavours to hold it in a determined angularposition so that the motor normally turns the shaft 14 and therewith thescraper 15 when it is in operation.

A ring 23, coaxial with the shaft 14, is connected with the plate 22 bymeans of stirrup members 24 which engage pins 25 on the plate 22. Thering presents on the outside thereof two raised portions or earns 26,27. Each of two brackets 28, 29 mounted on the frame 12 carries a limitswitch 30, 31, which are provided with pivotal actuating arms 32, 33having rollers 34, 35 which run around the outside of the ring 23. Theswitches 30, 31 are positioned at an angle of approximately 120 inrelation to each other and are also positioned so that, in the normalposition of the ring, i.e., the position the ring takes up when themotor is in its normal position determined by the spring 18 as shown inFIG. 2 the two rollers 34, 35 rest against the peripheral surface of thering at a distance from the cam 27 and 26 respectively.

The switch 30 is connected by suitable electrical means, indicated bythe dotted line 36 in FIG. 1, with the reversing valve 11 of theoperating cylinder 6 in such a way that, as the arm 32 swings inresponse to the pressure of roller 34, the valve 11 is set so thatpressure medium is passed to the cylinder in a manner which causesthrottle 5 to open. As is evident from the aforegoing, this takes placewhen the resistance to the movement of the scraper is so great that themotor, which rotates the shaft 14 in the direction of the arrow andwhich, at the same time, itself rotates around the shaft against theaction of spring 18 in the direction of arrow 38, makes as theresistance increases a deviation or swing of such magnitude that thering 23 is rotated to an extent whereby the cam 27 presses in the roller34. Thus, a certain quantity of settled solid material is removed,whereafter the motor, as a result of the reduced resistance, returns toits normal position, and the throttle closes as soon as the roller 34 isno longer actuated by the cam 27.

If the resistance to scraper movement is so great that the ringcontinues to be turned until the cam 26 meets the roller 35 of theswitch 31, the roller 35 causes the switch to close the valve, wherewiththe arrangement functions as described in the introduction when themotor is started or when an unnormally large obstacle is present, e.g.,a solid body at the bottom of the container.

We claim:

1. A sedimentation apparatus comprising a container having a loweroutlet for discharging sediment,

means normally closing said outlet,

a rotatable shaft extending through said container,

a scraper attached to the lower end of said shaft to move sedimenttoward said outlet upon rotation,

motor means connected to said shaft for rotating said shaft and scraper,

resilient means mounting said motor means on said container,

said resilient means comprising a spring mounted around the upper end ofsaid shaft and connected at one end to said container and at the otherto said motor means to permit said motor means to rotate around saidshaft when resistance to rotation of said scraper increases to apredetermined amount, and

first switch means mounted on said container for opening said outletclosing means when actuated,

said first switch means being actuated by the initial rotation of saidmotor means when the resistance to rotation of said scraper reaches saidpredetermined amount.

2. A sedimentation apparatus according to claim 1 which includes a ringconnected to said motor means for rotation therewith and mountedcoaxially with said shaft, and a cam surface on the outside of said ringwhereby rotation of said motor means and said ring causes said camsurface to actuate said first switch means.

surface on the outside of said ring for actuating said first switchmeans upon initial rotation of said motor means and said ring, and asecond cam surface on the outside of said ring spaced from said firstcam surface for actuating said second switch means upon further rotationof said motor means and said ring.

1. A sedimentation apparatus comprising a container having a lOweroutlet for discharging sediment, means normally closing said outlet, arotatable shaft extending through said container, a scraper attached tothe lower end of said shaft to move sediment toward said outlet uponrotation, motor means connected to said shaft for rotating said shaftand scraper, resilient means mounting said motor means on saidcontainer, said resilient means comprising a spring mounted around theupper end of said shaft and connected at one end to said container andat the other to said motor means to permit said motor means to rotatearound said shaft when resistance to rotation of said scraper increasesto a predetermined amount, and first switch means mounted on saidcontainer for opening said outlet closing means when actuated, saidfirst switch means being actuated by the initial rotation of said motormeans when the resistance to rotation of said scraper reaches saidpredetermined amount.
 2. A sedimentation apparatus according to claim 1which includes a ring connected to said motor means for rotationtherewith and mounted coaxially with said shaft, and a cam surface onthe outside of said ring whereby rotation of said motor means and saidring causes said cam surface to actuate said first switch means.
 3. Asedimentation apparatus according to claim 1 which includes a secondswitch means mounted on said container for closing said opening whenactuated, said second switch means being actuated by further rotation ofsaid motor means a predetermined degree beyond said initial rotation. 4.A sedimentation apparatus according to claim 3 which includes a ringconnected to said motor means for rotation therewith and mountedcoaxially with said shaft, a first cam surface on the outside of saidring for actuating said first switch means upon initial rotation of saidmotor means and said ring, and a second cam surface on the outside ofsaid ring spaced from said first cam surface for actuating said secondswitch means upon further rotation of said motor means and said ring.